The invention relates to a device on, for example, a carding machine for cotton, synthetic fibers and the like. The device comprises at least one flat bar with flat bar clothing, where the flat bar clothing is attached to the flat bar and is positioned opposite clothing on, for example, a main carding cylinder of the carding machine.
The flat bar of a known device has of a back part and a support body with an underside. A clothing strip (flexible clothing) that extends in a longitudinal direction of the underside is attached to the underside. The clothing strip comprises a support element having several textile layers in which a plurality of small wire hooks or clothing needle points are fastened. The clothing strip is attached with the aid of two clamps, straps, or clips along the longitudinal sides of the support body. With one end, the clamps encircle the longitudinal edge regions of the clothing strip and, with the other end, they engage recesses in the support body. In practical operations, the clamps consist of a sheet-metal strip, one longitudinal edge of which is punched into the textile material. During assembly, the textile material of the clothing strip is attached with considerable tension and is form fitting to the support body of the flat bar. In the process, the clamps exert tensile stresses in such a way that the textile material is deformed spherically away from the underside. Thus, the clothing needle points are also arranged in an undesirable manner along a convex enveloping curve, pointing toward the outside.
A set of flat bars produced in this way has an accuracy of 0.05 mm in height and evenness when not in use. As a result of use, the height differences in the set will increase to approximately 0.2 mm. The accuracy is improved only insignificantly through a re-sharpening of the clothing on the machine. Following a fiber-material throughput of approximately 400 t, the flat bar clothing is worn to such a degree that it must be replaced. The flat bar is clamped in for dismantling the sheet metal straps and the form-locking connection is reversed with the aid of a lever and pliers. The considerable forces required for the assembly and dismantling negatively effect the dimensional stability of the flat bar. Added to this are undesirable tolerances resulting from the production of the flat bar body. As a result of the aforementioned disadvantages, the clothing needle points of the clothed flat bar must be leveled by grinding.
According to a previous solution (shown in European Patent 0 887 445), the clothing strip is attached to a support, for example the base of a steel band. The flat steel band base is inserted between guide grooves that open toward the inside, in the edge regions of the flat bar underside, thus fastening the clothing strip to the flat bar. The production of this flat bar is quite involved with respect to production technology and assembly. It is particularly bothersome that the steel band underside and the guide grooves must be produced to exact dimensions to offer sufficient support during the operation. In addition, this makes replacement more difficult.
In contrast to the above, it is an object of the invention to create a device of the above-described type that avoids the aforementioned disadvantages. In particular, the invention makes it possible to produce a clothed flat bar with inherently stable form and makes it easier to produce the flat bar and replace the clothing strip.
The production and replacement of the clothed flat bar is simplified because the outside of the support and the support body for the flat bar fit together form-fittingly and the support is furthermore secured in the recess with an additional fastening element. Tolerances resulting from the production of the flat bar and the clothing as well as assembly (including dismantling) are thus reduced or eliminated. With the clothed flat bar according to the invention, an addition of the tolerances resulting from the assembly and dismantling of the flat bar clothing, the technologically damaging leveling and the decrease in the accuracy during use are advantageously avoided.
Particular embodiments of the invention provide a flat bar for use in a carding machine having a roller with clothing. The flat bar is for arranging opposite the clothing on the roller. The flat bar has a flat bar support body having a recess, a clothing support having a first side, the first side being positioned in the recess, flat bar clothing attached to a second side of the clothing support, the second side being opposite the first side, and at least one fastening element that secures the first side of the clothing support in the recess.